The present invention relates to air compressors. More particularly, the present invention relates to a multi-function dry air compressor system.
Electrical power handling equipment, such as transformers, often include a tank filed with oil in which the power handling devices or coils are disposed. The gas volume or ullage above the oil in the tank is often filled with dry air to avoid a moist air atmosphere that contaminates the oil due to oxidation and/or moisture absorption. Dry air for this purpose is generally air having a dew point of less than approximately −30° F. at one atmosphere pressure, which corresponds to a moisture content of approximately less than 235 ppm v/v. During installation or maintenance of the electrical power equipment, a high volume of the dry air is required.
To date, the dry air has generally been supplied from high pressure, refillable cylinders. However, the use of dry air cylinders has numerous drawbacks. The dry air cylinders need to be replaced on a regular basis. The cylinders are typically transported in pyramid trailers, rental cradles or semi-tube trailers. The trailers generally require a large vehicle for towing and need special hazmat endorsements prior to transport. Emptied cylinders require change over at an off-site location, thereby requiring transportation time between the electrical equipment site and the change over location. Once the cylinder trailer has arrived at the change over location, approximately 15-21 empty cylinders must be removed from the trailer and replaced by full cylinders, each full cylinder weighing approximately 200 pounds. Such change over often takes several hours such that the complete change over process, including transportation time, takes 10 or more hours which can cause significant delays during the installation or maintenance. Furthermore, the emptied cylinders also have to be returned to the vendor for refilling, resulting in additional time and costs.
In addition to using the dry air to fill the transformers or other electrical equipment, the dry air cylinders are also often used to supply breathable air to workers working in and around the transformers. In view of the criticality of the breathable air source, it is necessary to replace the cylinders more frequently to ensure the cylinders do not inadvertently empty, thereby leaving the workers without a sufficient supply of breathable air.
Accordingly, there is a need to supply dry air to a remote location that is cost effective and eliminates the need for frequent refilling of cylinders.